1. Field of the Invention
The present invention relates to a substrate carrying and processing apparatus which is adapted to carry and process a substrate, for example, a semiconductor wafer or LCD glass substrate.
2. Background Art
Generally, in production of semiconductor devices, a photolithography technique is utilized to form a thin film of ITO (Indium Tin Oxide) and/or electrode pattern on a substrate, such as a semiconductor wafer or LCD glass substrate. The photolithography technique is performed in a series of steps comprising; coating a photoresist on a substrate, exposing the resultant resist film which corresponds to a predetermined circuit pattern, and then developing the exposed pattern so as to form a desired circuit pattern of the resist film.
An apparatus for performing such processes is generally provided with a resist coating and processing unit adapted to coat and process a resist liquid on a substrate, a heating unit adapted to heat a substrate after being subjected to the resist coating and processing step and/or to heat a substrate after being subjected to the exposing step, a cooling unit adapted to cool a substrate after being subjected to the heating process to a predetermined temperature, and a developing unit adapted to develop a resist on a substrate by supplying a developing liquid thereto, wherein these units are stacked individually into a plurality of stages. The transfer and carrying in or carrying out of each substrate between the respective processing units is performed by using a carrying apparatus.
If the substrate is not cooled immediately after the heating process, there is a risk of occurrence of defects due to overheating or over-baking of the substrate. Thus, a pre-cooling unit is provided to have each substrate wait and pre-cool it before it is cooled to a predetermined temperature, wherein a plurality of substrate carrying apparatuses serve to carry respective substrates between the resist coating and processing unit and the heating unit, between the heating unit and the cooling unit, and between the pre-cooling unit and the cooling unit (e.g., see Patent Document 1).
In order to efficiently carry each substrate, corresponding to a time difference of each processing time for the substrate in each processing unit and enhance the throughput, delivery or transfer of substrates is performed by using separate substrate carrying apparatuses respectively adapted to move in two directions relative to a plurality of substrate storing sections, which are arranged into multiple stages to respectively store a plurality of substrates therein, and which are provided between processing blocks each provided with a plurality of processing units, or in an interface block (e.g., see Patent Document 2).
Depending on the type of the resist film to be used, the coating mode varies with cases, including the case of forming an antireflection film both on and under the resist film, the case of forming such an antireflection film either on or under the resist film, and the case of not forming the antireflection film and processing the resist film alone. Accordingly, the processing conditions for forming a coating film in the respective processing units, i.e., the coating and processing unit, heating unit, cooling unit and pre-cooling unit, should sometimes be changed depending on each lot. In such a case, and in such configuration that the coating and processing unit, heating unit, cooling unit and the like are provided in the same processing block, the flow mode to carry the substrate varies with alteration of the units to be used depending on the type of the resist film. Therefore, the carrying schedule for respective substrates should be more complicated. If the number of sheets of the substrates to be stored in each substrate storing section described above is significantly increased, the time for which each substrate must wait may be drastically lengthened.    Patent Document 1: TOKUKAI No. 2001-57336, KOHO (claims, paragraph [0046], and FIGS. 1 and 2)    Patent Document 2: TOKUKAIHEI No. 9-74127, KOHO (claims, paragraphs [0042] to [0043], and FIGS. 1 and 2)
However, in either of the apparatuses disclosed in the above Patent Documents, TOKUKAI No. 2001-57336, KOHO and TOKUKAIHEI No. 9-74127, KOHO, a plurality of (e.g., three or four) supporting pins are respectively provided at respective placing portions which are arranged into multiple stages or shelves for respectively storing a plurality of substrates, wherein each substrate is supported by using these supporting pins so as to carry each substrate to each substrate carrying apparatus. Accordingly, a particular height selected with consideration of transfer of the substrate relative to each substrate carrying apparatus must be provided in a space in which a sheet of substrate is stored in each substrate storing section, as such the number of the placing portions is limited by the height of the entire apparatus.